Currently, when a user signs up for data communication service, the service provider may provide the user, who is now a “subscriber”, with a palette of service plans from which to choose. One such service plan might allow the user to engage in an unlimited quantity of data communication for a fixed monthly recurring charge. Other service plans might provide different charges for different quantities of data, plus a per-unit charge for communication of data beyond the quantity allotted. For instance, one plan might allow the user to communicate up to 5 megabytes of data per month for $5.00 with a charge of $0.08 for each additional kilobyte, another plan might allow the user to communicate up to 10 megabytes of data per month for $10.00 with a charge of $0.07 for each additional kilobyte, and another plan might allow the user to communicate up to 30 megabytes of data per month for an MRC of $20.00 with a charge of $0.06 for each additional kilobyte.
To facilitate invoicing subscribers for their service plan, service providers typically implement record-generation and record-keeping functionality in their access networks. In particular, service providers may implement functionality to generate usage records in access network gateways, such as a packet-data serving node (PDSN), and may implement deep packet inspection (DPI) functionality along the communication path used by subscribers, typically in an entity referred to as a home agent (HA). Usage records are typically generated on a per-subscriber and per-session basis, and include such information as the session ID, the subscriber ID, the destination address for a data session, and/or the amount of usage (e.g., kilobytes of data, or minutes of voice communication) during a session, among other information. These usage records may then be used by a service provider for billing purposes, and in particular, to generate monthly invoices for subscribers.